Recently, there has been an increasing demand for applications that require multicast service. Multicast service provides transmission of a message from a base station to multiple members of a multicast group concurrently, in contrast to unicast service, in which a message is transmitted from the base station to a single user. Applications that require multicast service include group-oriented mobile commerce, military command and control, first-response team communications, education over wireless, and intelligent transportation management systems. With the increasing popularity of mobile handsets, it has become highly desirable to extend multicast service to the wireless environment. Several wireless technologies now support multicast service using a common multicast channel, for example, wideband code division multiple access, (W-CDMA), CDMA2000, and the IEEE 802.11 standard for wireless local area networks (WLANs).
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